The present invention relates to a scroll compressor which is used to compress a gas. More specifically, the present invention relates to a scroll compressor which is advantageously used for a booster connected to a city gas supply pipe to increase the pressure of a gas.
Generally, a scroll compressor comprises a casing, a fixed scroll member provided in the casing, which includes an end plate and a spiral wrap portion standing on the end plate, a driving shaft rotatably provided in the casing, and an orbiting scroll member orbitably provided at a distal end of the driving shaft, which orbiting scroll member is adapted to transfer a compressed gas from a suction opening to a discharge opening. The orbiting scroll member includes an end plate and a spiral wrap portion standing on the end plate. The wrap portion of the orbiting scroll member is adapted to overlap the wrap portion of the fixed scroll member so as to define a plurality of compression chambers.
In the scroll compressor of this type, the orbiting scroll member is subject to an orbital motion, with a predetermined orbiting radius (or eccentric distance) about the center axis of the fixed scroll member. Thus, a gas sucked in from the suction opening provided at an outer periphery of the fixed scroll member is compressed in each compression chamber between the wrap portions of the fixed and orbiting scroll members, and discharged to the outside through the discharge opening provided at a central portion of the fixed scroll member.
When the above-mentioned scroll compressor is applied to compressing a refrigerant for air conditioning or a cooling operation, since the pressure of the refrigerant (in gaseous form) at the suction opening is higher than atmospheric pressure, a problem arises, such that the refrigerant at the suction opening is likely to escape to the outside through a space between the outer peripheries of the fixed scroll member and the orbiting scroll member. Therefore, as a refrigerant compressor in the related art, a closed-type compressor has been employed, in which the main body of the compressor is confined in a container, together with an electric motor for rotating the driving shaft.
In a closed-type compressor, the inside of the container is shielded from outside air. Therefore, in order to cool the compressor which is heated during operation, a cooling method using a gas to be compressed by the compressor or a cooling method using a lubricant is required to be used.
When a closed-type compressor is used as a refrigerant compressor, it has no cooling problem. However, when it is applied to compressing a gas having a low heat capacity, such as a city gas, a cooling ability of the gas is insufficient, so that the compressor cannot be cooled to a satisfactory level.
On the other hand, in a cooling method using a lubricant, it is difficult to separate a compressed gas and the lubricant. This makes it difficult to apply the compressor to, for example, a city gas booster. Further, this method cannot be employed in an oilless-type compressor using no lubricant.
When an oilless-type compressor exposed to outside air is applied to compressing a high-pressure gas such as that in a city gas supply pipe, the gas leaks from the suction opening to the outside.
The present invention has been made, in view of the above-mentioned problems accompanying the related art. It is an object of the present invention to provide a scroll compressor which prevents leakage of a gas even when a gas having a pressure higher than atmospheric pressure is compressed.
The present invention provides a scroll compressor comprising:
a fixed-side member comprising a casing and a fixed scroll member provided in the casing, the fixed scroll member including an end plate and a spiral wrap portion standing on the end plate;
a driving shaft rotatably provided in the casing;
an orbiting scroll member orbitably provided at a distal end of the driving shaft, the orbiting scroll member including an end plate and a spiral wrap portion standing on the end plate, the wrap portion of the orbiting scroll member being adapted to overlap the wrap portion of the fixed scroll member so as to define a plurality of compression chambers;
a suction opening provided in the fixed-side member so as to communicate with the outermost compression chamber of the plurality of compression chambers;
a discharge opening provided in the fixed-side member so as to discharge a compressed gas from an inner compression chamber of the plurality of compression chambers to the outside; and
a seal member comprising an elastic member provided around an outer circumferential surface of the orbiting scroll member, so as to seal the plurality of compression chambers relative to outside air between the orbiting scroll member and the fixed-side member, the seal member having an opening on a radially inner side thereof and having a generally U-shaped cross-section.
The present invention also provides a scroll compressor comprising:
a casing;
a fixed scroll member provided in the casing, the fixed scroll member including an end plate and a spiral wrap portion standing on the end plate;
a driving shaft rotatably provided in the casing;
an orbiting scroll member orbitably provided at a distal end of the driving shaft, the orbiting scroll member including an end plate and a spiral wrap portion standing on the end plate, the wrap portion of the orbiting scroll member being adapted to overlap the wrap portion of the fixed scroll member so as to define a plurality of compression chambers;
a suction opening communicated with the outermost compression chamber of the plurality of compression chambers;
a discharge opening adapted to discharge a compressed gas from an inner compression chamber of the plurality of compression chambers to the outside; and
a seal apparatus provided on an outer circumferential surface of the orbiting scroll member, so as to seal the plurality of compression chambers relative to outside air between the orbiting scroll member and the fixed scroll member,
the seal apparatus comprising:
a grooved, annular seal mounting member having an opening, the annular seal mounting member being attached to the outer circumferential surface of the orbiting scroll member so that the opening of the groove faces the fixed scroll member; and
a ring-shaped seal member for providing an gas-tight seal between the fixed scroll member and the orbiting scroll member, the seal member being attached to the groove of the annular seal mounting member so as to allow a part of the gas to flow into the inside of the seal member and increase sealing performance of the seal member.
The foregoing and other objects, features and advantages of the present invention will be apparent from the following detailed description and appended claims taken in connection with the accompanying drawings.